I went into the old building. Here, in the teak-inlaid corridors and corniced offices, Philby, Burgess, Maclean, and Blunt were hunted down.. And here too we had fought MI5's most secret war over suspicions of an undiscovered mole at the heart of the Service.. Our suspect was the former Director-General of MI5, Sir Roger Hollis, but we had never been able to prove it..Hollis's friends had bitterly resented the accusation and for 10 long years both sides had feuded like medieval theologians, driven by instinct, passion, and prejudice..One by one in the 1970s the protagonists had retired, until finally the move to new offices signaled the end of the war.. But walking the corridors of Leconfield House I could still feel the physical sense of treachery, of pursuit, and the scent of the kill...

Signals intelligence Operational Platforms are employed by nations to collect signals intelligence, which is intelligence-gathering by interception of signals, whether between people (COMINT) or between machines ( ELINT), or mixtures of the two..Submarines are the original stealth platforms.. When no more than a mast breaks the surface, they immediately become radar targets, so virtually all modern submarines will have the minimum ELINT of a radar warning receiver.. Far beyond that, however, many submarines will penetrate hostile areas, raise SIGINT receiver masts, usually with some type of radar-observant covering, and listen.. Especially sophisticated SIGINT submarines may tap undersea cables..The US launched the first SIGINT satellites, followed by the Soviets..The biggest problem in joint intelligence is sharing, especially the now more-sensitive SIGINT, HUMINT, and MASINT. The next largest is damage to bilateral relationships, especially with the US...

I was born in 1916 at my grandmother's house in Chesterfield, where my mother had gone to stay while my father was in Norway for MI6.. There was a Zeppelin raid on nearby Sheffield that night, and I arrived very prematurely.. There were no hospital beds available because of the pressure of the war, but my mother kept me alive with an improvised incubator of glass chemical jars and hot-water bottles..After World War I my father rejoined the Marconi Company. He became a protege of Marconi himself and was made Head of Research.. We moved to a large house by the sea near Frinton. But this lasted only a few months, when we moved to a house on the outskirts of Chelmsford.. The house often resembled a disused wireless factory.. Radios in various states of disrepair and tin boxes filled with circuitry were hidden in every corner.. My father was an intense, emotional, rather quick-tempered man - more of an artist than an engineer.. As early as I can remember he used to take me out into the garden or onto the open fields above the Essex beaches to teach me the mysteries of wireless.. He spent hours explaining valves and crystals and showed me how to delicately turn the dials of a set so that the random static suddenly became a clear signal.. He taught me how to make my own experiments and I can still remember his pride when I demonstrated my crude skills to visiting guests like Sir Arthur Eddington and J. J. Thomson..MI6 had close connections with the Marconi Company after World War I, and my father retained his contact with them. Marconi had a large marine division responsible for fitting and manning wireless in ships.. It provided perfect cover for MI6, who would arrange with my father to have one of their officers placed as a wireless operator on a ship visiting an area in which they had an interest..Admiral Hall was a visitor to the house; he and my father would disappear into the greenhouse together for hours at a time to discuss in private some new development. My father also knew Captain Mansfield Cumming, the first Chief of MI6.. He admired Cumming greatly, for both his courage and his technical ability.. He knew Captain Vernon Kell, the founder of MI5, much less well, but did not like him.. As with Oxford and Cambridge, people are usually disposed either to MI5 or to MI6, and my father very definitely leaned in favor of MI6...